1. Field of the Invention
The present invention relates to an image forming apparatus capable of forming an image by using photosensitive toner particles having at least one color former.
2. Description of Related Art
Toner particles having microcapsules are described in the U.S. patent application No. 07/570,594 abandoned. Each of the microcapsules encapsulates therein a color former, such as a dye-precursor, and changes mechanical strength according to the amount of the irradiated light to which it is exposed. Further, an image forming apparatus capable of forming an image on a recording medium by employing the above-mentioned toner particles is disclosed in the U.S. patent application No. 07/570,594 abandoned and U.S. Pat. No. 5,060,020. According to the image recording method of the image forming apparatus, after being exposed by an irradiated light, pressure is applied to those toner particles. Then, those toner particles which have not increased in mechanical strength are ruptured by the pressure development, so that an image is formed on a recording medium. The image forming apparatus of the type mentioned comprises a toner particle coating mechanism for coating those toner particles held by a carrying member onto a supporting member, such as a supporting drum, by using static electricity, an exposing mechanism for exposing those microcapsule toner particles based on an image information, and a microcapsule rupturing mechanism for rupturing those capsules such that the color former flows out from each of the ruptured microcapsules.
However, in the conventional image forming apparatus, there is the possibility that those photosensitive toner particles can not be uniformly coated on the supporting member owing to the differential among the amount of electricity applied to each of those toner particles. Therefore, it is problem that a formed image has color shading (uneven color), that is, a light colored part, or a dropped color, that is, a non-colored part.